Relays have several important uses in electronics. A relay is powered by a small electric with the ability to turn a larger electrical current on or off, like a switch. Joseph Henry, an American electromagnetics scientist, is credited with creating the concept of switching large electromagnets on and off.

Relays can be utilized in different ways depending on what is needed. The most common uses include controlling heavy motors and being a tool in switch circuits. Relays can be used in home automation projects through microcontrollers to switch AC loads, to schedule a time or condition for a heavy load to turn on or off and can be used to disconnect a load from its supply in the case of fa failure as a safety precaution.

There is a relay for every event or use imaginable. There are electromagnetic relays, thermal relays, power varied relays, and multidimensional relays all ranging in size, use, and ratings. In this article we will be covering electromagnetic relays, solid state relays, hybrid relays, thermal relays, and reed relays.

Electromagnetic relays are made up of electrical, mechanical, and magnetic components with coil to mechanical contact points. When the coil gets stimulated by a supply system, the mechanical contacts open or closed like a gate.

Solid state relays use stationary components to perform a switching program. The control energy needed to power the relay is lower in comparison to the output power leads to a higher power gain when compared to electromagnetic relays. These relays also are equipped with photo coupled SSR where an LED control signal is detected by a photo-sensitive semiconductor device. This photo detector is used to trigger the TRIAC or SCR gates to switch the load.

Hybrid relays have two parts, electromagnetic relays and electronic components. Each relay contains and input and output part. The input part is made up of electronic circuitry while the output part includes the electromagnetic relay.

Thermal relays are affected by heat and can reflect temperature change by changing the position of the contacts through use of the temperature sensors. Their main use is in motor protection to prevent overheating and are also named thermal overload relays.

Reed relays are made up of two magnetic strips, called a reed, that is sealed within a glass tube. When a magnetic field is applied to the system, the reed moves to operate the switching mechanism.

Now most importantly, how do relays work? There are four structures to a relay: a frame, coils, armature, and contacts. When a coil is electrified by a current, the coil produces a magnetic field. Since the coil is now magnetic it now attracts a ferrous plate, which is a component of the armature. On one end of the armature, a metal frame allows the device to pivot. This will help facilitate the change from normally open (NO), where there is open contact for the relay to energize, to normally closed (NC), where there is close contact.

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The next time you’re outside, turn your eyes to the sky and you will most likely see a few vapor trails above us. These are the white wispy lines that jet engine planes paint across the great blue sky as they zoom across the horizon. These lines are made by the engines inside the plane that powers them, specifically, jet engine propulsion. This type of engine converts energy rich liquid fuel into a powerful force called thrust. The thrust, in combination with lift, forces air past the wings to power it into the sky and enable flight. Let’s explore how jet engines function and how they vary from piston engines.

Jet engines are similar, yet different, to piston engines in vehicles. A piston engine utilizes cylinders that house pistons which move back and forth to provide power. A jet engine forces gas past the blades of a turbine which make it rotate. In piston engines, fuel is transferred into the cylinders with air from the atmosphere and undergoes a process called combustion. This occurs when burning fuel and air expand and raise the temperature within the pistons, causing them to move back and forth. The pistons drive the crankshaft that powers the cars wheels which enables it to move. The amount of power a piston engine can produce is directly correlated to how big the cylinder is and how far the piston moves. This concept of combustion creating propulsion is mirrored in jet engines.

Instead of using cylinders to power the pistons, a jet engine consists of a long metal tube that carries out the same functions that the cylinders do. Think of it as a thrust making production line. Air is drawn through an intake, compressed by a fan, mixed with fuel which causes combustion, then fired out through an exhaust system. Because this process is occurring at a constant rate, a jet engine is capable of producing a constant power stream that is much stronger than a car engine. A jet engine also burns more fuel since there is a constant need for it. Another area where piston engines vary is in the exhaust systems; jet engines pass the exhaust through multiple turbine stages to extract as much energy as possible.

A more technical name for a jet engine is a gas turbine. As the exhaust gas passes the turbine and causes it to rotate, the plane itself moves forward. This can be better understood by Newton’s third law of motion, which states, for every action there is an equal and opposite reaction. The force of the exhaust gas shooting backwards inevitably makes the plane propel forward. The turbine plays a crucial role in the operation of jet engines, making them a vital component.

At NSN Purchasing, owned and operated by ASAP Semiconductor, we can help you find all the jet engine parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at or call us at +44-142-035-8043.

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It’s an exciting time for the helicopter industry—new innovations and upgrades are on the forefront of technological development for Helicopters. Advancements in overall structure, engine components, and design are changing the way we conceptualize— and use—these aircraft. Traditional rotor systems are getting a facelift, and Bell is one of the companies paving the way for the future of helicopter operation.

Conventional rotor systems in modern helicopters suffer from technological advancement nuances. High vibratory loads, susceptibility to ground resonance instability, low control power, and poor performance in high speed/load conditions are a few examples of areas for improvement. To counter these deficiencies and expand a helicopters potential, many new rotor systems are being researched and developed. One in particular eliminates the tail rotor completely using a method called an anti-torque system. The tail rotor is replaced with a large fan, or blower, that blows air in the same direction the helicopter is traveling. A natural torque factor is applied between the main rotor and the helicopters fuselage during flight, necessitating a balancing counter torque force. Creating this force can be achieved with an internal fan that produces a large amount of air flow. There are several advantages for having an internal fan as opposed to an external rotor; among them are increased safety and lesser probability for rotor stall.

Bell, a leading manufacturer of helicopter, is a prime example of the rapid advancements occurring in helicopter technology. The company is currently developing new anti-torque systems and revamping the way helicopters perform, look, and operate. Bell engineers are researching a hybridized propulsion engine system. This will combine advanced thermal engine cores with electric distribution and motors to power the anti-torque system, resulting in better control and simpler vehicle operations. They are also exploring the implementation of morphing rotor blades, changing the way aircraft fly. This technology enables the aircraft rotor blades to transform according to different flight regimes and conditions. The ends of each blade have the capability to shift, angling to the right for better maneuverability.

Another innovation on the forefront of Bell’s agenda is next generation flight control technology. At the heart of Bell’s “fly-by-wire” system are three independent flight control computers. Once the computers receive digital commands from the pilots, the system calculates the optimal method to achieve the directive; ensuring the aircraft is operating at peak performance and is supported by extra redundancies.

These new technologies have made their way to the military as well. The military has adopted the idea of getting rid of tail rotors; they are looking to revamp their fleet of helicopters by 2030. The new Sikorsky-Boeing SB-1 Defiant is designed with two counter-rotating rotors and a push propeller that takes the place of a tail rotor. This allows the aircraft to maneuver better and travel faster than ever before, reaching speeds of 287 miles per hour. The Defiant is planned to replace the UH-60 Black Hawk, which has been in operation since 1979.

Keep an eye out for exciting next generation systems as Helicopters approach this technological revolution.

At NSN Purchasing, owned and operated by ASAP Semiconductor, we can help you find all the helicopter parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at or call us at +44-142-035-8043.

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The concept that led to propeller propulsion was derived from the rotating screw design, invented by Archimedes in 200 BC. This design was used to lift water from wells and was an inspiration for Leonardo Da Vinci’s flying machine. Although his helicopter-like design was never built, it inspired many aviation innovators. By the mid-1700s, the rotating screw design was also used in marine propulsion.

It wasn’t until the early 1900s that propellers were effectively used for flight. The Wright brothers used their wind tunnel test to study the aerodynamics applied to propeller blades and realized that propellers should be shaped more like a wing than a screw, and that it’s more efficient to add a twist along the length of the propeller blade. Today, propellers come in a vast array of styles that vary in size, shape, material, and application.

Propellers transmit power by converting rotational motion into thrust. They are attached to shafts and receive their energy supply from different types of engines. Once the propeller is spinning, it begins producing forward thrust. This can be explained through Bernoulli’s principle and Newton’s third law of motion. Bernoulli’s principle states that an increase in a fluid’s speed occurs simultaneously with a decrease in pressure or a decrease in the fluid’s potential energy. Newton’s third law of motion states that when body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude but opposite in direction of the first body.

Propellers have angled blades because it increases its speed capabilities and requires less force. Propeller blades are twisted because different parts of a propeller move at different speeds. To ensure that they produce a constant thrust at each point, the angle of attack needs to be different along the blade. The pitch, or angle of attack, varies under different scenarios.

Some aircraft— mainly lighter ones— have fixed pitch propellers: the blades are permanently fixed to the hub. Larger and more advanced aircraft have variable pitch propellers which include adjustable pitch propellers, controllable pitch propellers, and constant speed propellers. Adjustable pitch propellers allow the operator to adjust the pitch while grounded. Controllable pitch propellers allow the operator to adjust pitch during flight. Constant speed propellers automatically adjust pitch during flight. One of the benefits of having variable pitch propellers is that they have the ability to feather if an engine fails. This means that the blades are turned edge on, making a shallow angle to oncoming air, which minimizes drag and allows an aircraft to fly on the other engines or glide.

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One of the most important parts of any rotorcraft is undoubtedly the rotor. But the blades are a close second. Afterall, for rotorcraft, the rotational movement of the blades is the only reason that the aircraft can even achieve lift and fly.

For rotorcraft like helicopters, lift is achieved when the rotor blades (airfoil) meet the oncoming airflow and deflect them, creating a change in the direction of the airflow, which results in an area of low pressure forming behind the leading edge of the upper surface of the blade. In turn, this pressure gradient causes the air flow to accelerate down along the upper surface. Simultaneously, the airflow under the blade is rapidly slowed or halted, causing an area of high pressure, also causing the airflow to accelerate along the upper surface. The two sections of the airflow leave the trailing edge of the blade with a downward component of moment, producing lift. In order to withstand the airflow and effectively be lifted, the blade must be strong and durable enough. Therefore, it’s important to test the blade flex.

Rotor blades are dynamic devices, so of course it’s important to regularly inspect and test their functionality. However, equally important is a static test to verify the strength and mechanical properties of the blades. Because the environmental conditions and operating conditions of the blades can vary greatly, it’s good to make sure, during the manufacturing process, that everything is up to standard.

The static test is done by mounting the rotor blade horizontally on a stationary fixture at one end, a hydraulic ram at the other with LVDT (linear variable differential transformers) displacement sensors arranged along the length of the blade, and a strain gage load cell inserted between the hydraulic ram and blade tip. Pressure is applied to the ram, flexing the blade. Meanwhile, the load cell senses the amount of force while the LVDTs measure the amount of bending. These two readings are calculated as a ratio of force to bending and help determine the strength and flexibility of the blade. The ideal ratio is typically set by the OEM (original equipment manufacturer).

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The propeller is the one of the most vital parts on your aircraft, and one of the most vulnerable. The aircraft propeller is the main component used to generate thrust, consistently stressing the propeller. The likelihood of the propeller sustaining damage is substantially higher than it is for the rest of the airframe. So, it’s important to care for the propeller and conduct regular visual inspections. Fortunately, proper propeller care doesn’t require a specialized technician, nor will it take a lot of time. By following these few easy steps, you can remain vigilant on your propeller’s condition and remain confident when cruising at 15,000 feet.

The first place to begin is the preflight visual inspection. Make it a habit to regularly take an extra minute or two to inspect the propeller. When conducting the visual inspection make sure to keep an eye out for any visual damage on the aircraft propeller blades. You should be on the lookout for any signs of cracks, chips, dents, gouges, and erosion. To be completely thorough, make sure there’s no missing hardware. It’s a good idea to lightly drag your hand across the propeller to help you detect any abnormalities. If there are any discrepancies, delay your flight and address the issue.

As you may know, the aircraft should only be moved utilizing proper ground support equipment, such as a tow bar, to safely move the aircraft. This is the easiest precautionary action you could take to avoid unnecessary damage to your aircraft. Cutting corners may save time, but you’re much better off following the correct procedures from beginning to end. Pushing and pulling on the prop is a perfect recipe for a trip to the repair station.

Lastly, stay on top of maintenance and overhaul schedules. Maintenance intervals can be based on calendar time or flight hours, so be sure to keep track. Following the manufacturer’s recommendations will help prevent any major accidents from occurring.

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